The present invention relates to a pressurizing mechanism for a con""rod (connecting rod) used in a breaking and dividing device (fracture process) for the connecting rod of an internal combustion engine or the like.
The process of breaking and dividing a connecting rod, hereinafter referred to as a con""rod, as follows: As shown in FIG. 5, a con""rod 1 is made in prior art in such a way that a con""rod main body 2 and a bearing cap portion 3 are formed as one piece, for example, by sinter forging, and a notch 5a is made in a face which is to be divided. This face is on the inner surface of a bearing portion 5 on a large end portion 4 of the con""rod.
A small end portion of the con""rod 1, as shown in FIG. 5 and FIG. 6, is fitted onto a small end reference pin 12 carried on a support stand 11. Left and right seats 3a of the bearing cap portion 3 are mounted on a movable plate 14 on the bearing cap portion side of the large end portion 4. The plate 14 is located face to face with a stationary plate 13 which is on the main body side of the large end portion 4 and both plate 13 and plate 14 are on the support stand 11. Tips 15a of a movable pressing portion 15 are pressed to be in contact with seats 3a. Further, on the stationary plate 13 on the main body side, an escaping force receiving pin 16 is mounted so as to be in contact with a part of a shoulder 4a formed on the bearing cap portion 3 of the large end portion 4 of the con""rod 1. When the con""rod is so mounted on platform 11, a wedge 18 is forced into a split mold 17 fitted into the bearing portion 5 on the large end portion side, and consequently, the main body 2 and the bearing cap portion 3 are broken and divided at the notch 5a. Furthermore, reference numeral 19 denotes a guide plate for the movable plate 14, which is fixed on the support stand 11.
A mechanism in which the notch 5a is automatically formed so that breaking and dividing may securely be performed has been disclosed in Japanese Laid-Open Patent Application No. H6-91438. As described in that application, left and right expansion molds (a split mold) are provided face to face in the direction in which the main body and the bearing cap portion are to be separated from each other, in a large end hole, or bearing portion. A punch or wedge to be forced into a mid position thereof is provided, and breaking chips arranged with the tips facing to the inner surface of the large end hole bearing portion are provided at both ends at right angles to the direction in which the bearing cap portion is broken and separated by the punch. By forcing the punch (wedge), a load in the breaking and separating direction is given to the bearing cap portion or the like, and at the same time, the breaking chips 14 and 15 cause a concentrated load to be applied to the portion to be broken and separated. Accordingly, the part to be broken and separated can easily be deformed, and it is possible to securely make this part the breaking start point, and in the meantime, this can automatically be performed with no trouble by forcing the punch.
However, in a mechanism like the one described in the Publication, in which a notch is not formed in advance and a concentrated load is applied to the portion to be broken and separated by breaking chips from the inside of the large end hole (bearing portion) by utilizing the forcing of the punch (wedge) for giving a load in the breaking and separating direction to the bearing cap portion or the like, this concentrated load is applied suddenly in some cases, and therefore as shown in FIG. 7, the breaking and separating (dividing) are finished in the state shown by A, B where the breaking and separating are deviating from the line axe2x80x94a passing through the face to be broken and divided in some cases, and there are some cases where it cannot be used as a con""rod.
The present inventors have found as a result of research that the breaking and dividing of a con""rod can be performed precisely at the face to be broken and divided and with only a small deformation, by performing the breaking and dividing while applying force to points on the outside of the bearing cap portion of the large end portion of a con""rod, and have reached the present invention.
It is an object of the present invention to provide a pressurizing mechanism for breaking and dividing a con""rod, in which a wedge is forced through a split mold into a bearing portion on the large end portion side of a con""rod made in such a way that the bearing cap portion included in the large end portion and the main body side to be connected to the cap portion are manufactured as one piece. Breaking and dividing the main body and the bearing cap portion is performed so that the main body and the bearing cap portion may be broken and divided precisely at the face to be broken and divided, and further, the deformation at that moment can be made minimum.
In order to achieve the above object, a pressurizing mechanism of the con""rod breaking and dividing device of the present invention includes a mechanism to press a point to be broken and divided on the outside of the large end portion of the con""rod. In addition, a wedge is forced through a split mold into a bearing portion on the large end portion side of a con""rod made in such a way that a bearing cap portion included in the large end portion and a main body side to be connected to the cap portion are formed as one piece so as to break and divide the main body and the bearing cap portion.